Convicted killer Robert Chambers was in police custody again last night after cops discovered his license was suspended during a traffic stop, sources told The Post.

The Preppy Killer – who served 15 years for the 1986 killing of Jennifer Levin in Central Park – was pulled over by police around 7:20 p.m. at the Harlem River Drive and East 132nd Street when eagle-eyed Police Officer Michael Kelly noticed that his car was missing an inspection sticker, sources said.

He was hauled into the 32nd Precinct station house after it was learned his license was suspended earlier this month for failing to answer a summons.

Police found an “unknown substance” in Chambers’ wallet and in the car, as well as two straws and a piece of tinfoil, all containing powder residue, sources said.

Cops also found a macabre – although legal – stash in the 1999 Saab.

Chambers was driving around with six boxes full of press clippings and books relating to his crime.

The unshaven Chamber cooperated with cops and was placed in a holding cell with about a dozen other prisoners, a police source said.

“He’s not happy, but I guess he knows the routine by now,” the source said.

Police charged Chambers only with driving on a suspended license, the sources said.

He was expected to be held overnight and arraigned this morning.

Cops also found a prescription bottle containing unidentified pills, the sources said.

Chambers, 38, told cops the pills were prescribed to help him avoid indulging in his addictions, sources said.

He developed a drug problem in prison and spent more than four years in solitary confinement. The tall and handsome killer convinced female groupies to visit him in prison and perform sexual favors for other inmates who would then supply him with drugs.

When he left the upstate Auburn Correctional Facility he told The Post that he is clean and goes to AA meetings.

Chambers, then 18, spent the early-morning hours of Aug. 26, 1986 drinking with Levin in an Upper East Side bar. After the bar closed, the couple headed to Central Park, where Chambers strangled her.

When questioned by cops, Chambers initially denied knowing Levin, and said scratches on his face came from a cat.

He eventually admitted to cops he throttled Levin – but claimed it was an accident that occurred during rough sex.

In March 1987, Chambers pleaded guilty to first-degree manslaughter and burglary while a trial jury deliberated two counts of second-degree murder against him. He was sentenced to five to 15 years in prison.

About a month after Chambers reported to prison, a home video surfaced showing him twisting the head of a doll and saying, “Oops, I think I killed it.”

Chambers was denied parole several times and in December 2002 skipped a parole hearing, choosing instead to serve his full sentence.